Spruce beetle (Dendroctonus rufipennis) and mountain pine beetle (Dendroctonus ponderosae) are both primary bark beetles native to the forests of western North America. Both species have experienced extensive outbreaks in the past two decades, which are partially attributed to climate change. Although both species are affected by climate change, the manner in which they are affected differs. Mountain pine beetles disturbance levels are predominately influenced by climate change through range expansion as more pine-dominated areas become climatically suitable for their life cycles. Spruce beetles however are already found throughout the entire range of their host spruce trees and are affected through a change in development time rather than range expansion. In either case, regardless of the mechanism, climate change provides opportunities for increased disturbance levels from both spruce beetles and mountain pine beetles in western forests, creating future forest management challenges.